Stealthy Attacks in Cloud-Connected Linear Impulsive Systems

This paper studies a security problem for a class cloud-connected multi-agent systems, where autonomous agents coordinate via a combination of short-range ad-hoc communication links and long-range cloud services. We consider a simplified model for the dynamics of a cloud-connected multi-agent system and attacks, where the states evolve according to linear time-invariant impulsive dynamics, and attacks are modeled as exogenous inputs designed by an omniscent attacker that alters the continuous and impulsive updates. We propose a definition of attack detectability, characterize the existence of stealthy attacks as a function of the system parameters and attack properties, and design a family of undetectable attacks. We illustrate our results on a cloud-based surveillance example.